The present disclosure relates to AA alkaline batteries and AAA alkaline batteries.
Alkaline batteries have larger capacity than manganese batteries. However, further increase in the capacity of the alkaline batteries is still required. To this end, various techniques such as a technique of loading with positive and negative electrode active materials at higher densities and a technique of fully utilizing the space in a battery case while maintaining the external dimensions of the battery case within the standards are proposed.
Alkaline batteries have been conventionally used in a small current (hereinafter, referred to as low-rate current) range of 100 mA or less. However, to meet a recent demand for driving digital still cameras or the like with alkaline batteries, the use of alkaline batteries in a large current (hereinafter, referred to as high-rate current) range of 500 mA or more has been investigated. Under this circumstance, some alkaline batteries are designed with a focus on enhancement of discharge characteristics in the high-rate current range. For such alkaline batteries, a technique of increasing the porosity in a positive electrode material mixture so as to store a larger amount of an electrolyte in a positive electrode, for example, has been studied.
For example, Japanese Laid-Open Patent Publication No. 9-180708 discloses that the use of a positive electrode material mixture pellet having a pore quantity ranging from 0.14 cc/g to 0.24 cc/g, both inclusive, as a positive electrode enhances discharge characteristics in the high-rate current range.
In addition, International Publication WO 94/024709 discloses that setting the zinc density at 1.4 g or more per 1 (one) cm3 of a negative electrode volume and the manganese dioxide density at 2.7 g or more per 1 (one) cm3 of a positive electrode volume allows the capacity of each of the positive and negative electrodes to be 0.48 Ah or more per 1 (one) cm3 of the internal volume of the battery.
Further, Japanese Laid-Open Patent Publication No. 2002-75338 discloses that the amounts of a positive electrode active material and an electrolyte are both increased in order to increase the discharge capacity of a battery and to enhance discharge characteristics of the battery in the high-rate current range. Specifically, a positive electrode material mixture contains a positive electrode active material and a conductive agent and also contains fine gaps. This positive electrode material mixture is formed in such a manner that fine cracks occurring in the positive electrode material mixture when an electrolyte is held therein first appear between particles of the positive electrode material mixture.